In most cases the CD30/DV30 is normally used in conjunction with the AR30/DR30 receiver, which has a trigger function to power the CD30/DV30 on and off automatically.
With this in mind, the default mode for remote operation is a multi-functional control mode, making the the CD30/DV30 remote a 'system' remote that will also control the AR30/DR30. As such, the power button on the CD30/DV30 remote will power the AR30/DR30 on and off, which in turn powers the CD30/DV30 on and off.
However, if you do not have an AR30/DR30 and are using the CD30/DV30 as a stand-alone CD/DVD player, the remote control must be set/locked to the CD/DVD mode. This is done by re-inserting the batteries whilst holding down the CD or DVD button (depending on whether it is a CD30 or DV30) on the remote control, as detailed in the user manual.
The CD30/DV30 remote will now power on and off the CD30/DV30.